Novel elastomeric graft copolymers

ABSTRACT

6-Nylons and 12-nylons having primary amino end-groups and an average degree of polymerization of about 5-60 are grafted onto elastomeric trunk polymers having anhydride groups, vicinal carboxylic groups, or carboxylic groups adjacent to alkoxycarbonyl groups by heating a mixture of the nylon and the trunk polymer, preferably under high shear conditions for about 1 minute or less to 30 minutes or more above the melting temperature of the nylon. The resulting elastomeric graft polymers are suitable for fabricating into a variety of articles, such as, for example, wire jacketing, hose, belts, seals, gaskets, and low pressure tires.

BACKGROUND OF THE INVENTION

This invention relates to novel thermoplastic, elastomeric polymericmaterials formed by grafting short chain 6-nylons or 12-nylons ontorubbery trunk polymers.

Most elastomers can be molded or extruded into various shapes. Thefabricated articles may include, for example, automotive trim, bumperinserts, and hoses. Usually, these elastomers have low strength and mustbe crosslinked after being shaped into the desired article. The curingstep usually requires compounding with suitable agents such as sulfur,peroxides, and the like, before shaping. The thermal sensitivity of thecompounded curable compositions may cause premature curing ("scorch")and loss of plasticity. Radiation cures, which do not involvecompounding, are generally only effective with thin cross sections;degradation may compete with crosslinking. Furthermore, cured scrap andcured shaped articles which have defects are not conveniently reused.Accordingly, it would be desirable to have thermoplastic elastomerswhich require no cure and can be shaped repeatedly by heating to givearticles having satisfactory strength and dimensional stability at thetemperatures prevailing during their use. Blends and grafts of polymersare known in the art to give thermoplastic products which often haveimproved properties.

Tutorskii et al., Journal Polymer Sc. 61, 97-106 (1962) reports graftingof ε-caprolactam onto carboxylated butadiene-styrene rubbers by heatingthe rubber and the lactam above 200° C. in the presence of borontrifluoride.

Chapman et al., Journal Polymer Sc. 34, 319-335 (1959) report thepolymerization of ε-caprolactam at elevated temperatures in the presenceof a copolymer of styrene with methyl acrylate, acrylic acid, or maleicanhydride. Gelling was observed in several instances, especially withstyrene/maleic anhydride copolymers.

U.S. Pat. No. 3,484,403 describes certain hot melt adhesive and coatingcompositions based on blends of polyamides with grafts of unsaturateddicarboxylic acids or their anhydrides on polyolefin backbone.

U.S. Pat. No. 3,261,885 discloses block-graft copolymers obtained bysubjecting to high shear conditions at 50°-350° C. a mixture of C₂ -C₄olefin or styrene copolymers with up to 50 weight percent of anotherunsaturated monomer with various synthetic linear polyamides in thepresence of free radical generators.

Yurkevich et al., Khimicheskie Volokna No. 3, 11-13 (1971) (1972,Consultants Bureau's English translation) reports experiments with graftcopolymers of polycaproamide (6-nylon) with vinyl monomers, such asacrylonitrile, styrene, acrylic acid, and various acrylic esters. Whileno experimental details are given, it appears that the vinyl monomerswere grafted onto polycaproamide. The resulting products were examinedfor possible use in melt spinning of fibers.

U.S. Pat. No. 3,676,400 discloses melt extrusion of mixtures of certainamino-terminated polyamides having molecular weights of at least 2000,and preferably 10,000-40,000, with copolymers of 2-monoolefins andunsaturated mono- or dicarboxylic acids.

None of the prior art suggests grafting of amino-terminated 6- or12-nylons on rubbery materials to produce thermoplastic elastomers ofimproved mechanical properties.

SUMMARY OF THE INVENTION

According to this invention, there is provided a class of novelthermoplastic, elastomeric compositions, which are made by graftingshort chain primary amino-terminated 6-nylons or 12-nylons onto uncuredelastomeric trunk polymers having reactive sites such as anhydride,adjacent carboxyl and alkoxy carbonyl, or two adjacent carboxy groups.These graft copolymers can be readily shaped and molded at temperaturesabove the melting point of the nylon component; when cooled totemperatures below 100° C., they display greatly enhanced strengthrelative to that of cured trunk polymers.

For the purpose of the present invention, the term "6-nylon" means anNH₂ -terminated linear polymer of ε-caprolactam. The term "12-nylon"means an NH₂ -terminated linear polymer of ω-laurolactam. Suitable shortchain 6- or 12-nylons have an average degree of polymerization of about5-60 and contain no primary or secondary amino groups other than oneterminal NH₂ group.

In the resulting graft copolymers of the present invention the polyamidebranches are believed to be attached to the trunk through imide or amidelinkages. An imide can be represented, for example, by the followingFormula (1) ##STR1## wherein

the wavy lines represent the trunk copolymer;

Z is ##STR2## or --OH,

R¹ and R² being independently selected from hydrogen, a C₁ -C₁₈ alkyl,benzyl, and a C₅ -C₆ cycloalkyl; or, taken together, being --(CH₂)₄ --,--(CH₂)₅ --, --(CH₂)₂ --O--(CH₂)₂ --, or ##STR3## where R³ is a C₁ -C₆alkyl; with the proviso that only one of R¹ and R² can be hydrogen;

m is 5 or 11; and

x is a positive number having an average value of about 5-60.

In addition to or instead of the amide groups, such as shown in Formula(1), amide linkages may be present in the graft copolymer. The amidelinkages may form as intermediates in the first stage of the graftingprocess or may be the predominant groups if grafting is stopped at thatstage.

DESCRIPTION OF THE INVENTION

The trunk polymers useful in the present invention are elastomeric. Asapplied to the trunk polymers, the term "elastomeric" is defined to meanthat when they are crosslinked, they are capable of recovering fromlarge deformations quickly and forcibly. Free from diluents, thecrosslinked trunk polymers retract within one minute to less than 1.5times their original lengths after being stretched at 18°-29° C. totwice their lengths and held for one minute before release. However,these trunk polymers are used in the process of this invention inuncured state. The graft copolymers of this invention are elastomeric,as defined above for the trunk copolymers, without being subjected tovulcanization or curing. Grafting of polyamide side chains on an uncuredtrunk polymer results in an elastomeric graft copolymer.

The uncured trunk polymers may carry additional functional groups suchas, for example, carboxyl, alkoxycarbonyl, alkoxyl, and cyano. Hydroxylor amino groups, however, are unsuitable because they can interact withthe graft sites to form thermostable crosslinks causing a loss of thedesired thermoplasticity. The trunk copolymers contain, on anumber-average basis, about 300 to 50,000 (preferably 1,000 to 5,000)chain atoms and about one to 50 amine-reactive sites per 1000 chainatoms of the trunk copolymer. The side-chain polymer will, in general,be shorter than the trunk copolymer, ranging in length from about 25 to1,000 chain atoms, preferably about 30 to 300 chain atoms. The trunkpolymers must be sufficiently stable to withstand heating during thegrafting step and the subsequent processing into shaped articles. Suchpolymers usually are copolymers of the active site-containing monomerwith at least one other monomer, for example, various α-olefins such asethylene, propylene, 1-butene; dienes such as butadiene, isoprene,1,3-hexadiene, 1,4-hexadiene, and norbornadiene; styrene, and itsring-substituted derivatives; acrylic and methacrylic acids, esters andnitriles; vinyl esters such as vinyl acetate and butyrate; vinyl ethers,vinyl sulfides, and the like. Representative trunk copolymers can bemade by copolymerizing the site-containing monomer with such othermonomers as, for example, ethylene and an alkyl acrylate; ethyl or butylacrylate; ethylene and vinyl acetate; ethylene and acrylonitrile; andethylene and methyl vinyl ether.

The amine-reactive sites on the trunk copolymers are provided bymonomers which are either copolymerized during the preparation of thetrunk copolymer or are grafted onto a previously existing polymer.

Copolymerization of the monomer providing the amine-reactive site willbe possible when all the monomers are polymerizable by conventional freeradical catalysis. Ethylene, alkyl acrylates, conjugated dienes,styrene, vinyl ether, vinyl sulfides, acrylonitrile, vinyl esters,acrylic acid, methacrylic acid, and the like, are examples of suchcomonomers.

Free radical-polymerizable monomers, which can be incorporated into thetrunk copolymer to provide the amine-reactive sites, frequently have theformulae ##STR4## where X and Y are independently selected from H, Cl,C₁ -C₈ alkyl, and phenyl; with the proviso that one of X and Y must beH; and W is H, C₁ -C₁₀ alkyl, phenyl, naphthyl, or substituted phenyl ornaphthyl where the substituents are C₁ -C₁₀ alkyl, halogen, or C₁ -C₁₀alkoxy groups. Other possible monomers, which are not represented byeither formula (2) or formula (3), are itaconic acid, its anhydride, andmonoesters.

Compounds representative of formula (2) include maleic anhydride andcitraconic anhydride. Compounds representative of formula (3) includemaleic acid, citraconic acid, fumaric acid, mesaconic acid, andmonoesters of maleic and fumaric acids, including the methyl, ethyl,isopropyl, propyl, butyl, tert-butyl, amyl, isoamyl, hexyl, octyl,decyl, phenyl, 1-naphthyl, 2-naphthyl, 2-methylphenyl, 2-ethylphenyl,2,5-dimethylphenyl, 4-isopropylphenyl, 4-butylphenyl,3,5-dimethyl-3-propylphenyl, 3-decylphenyl, 4-tetradecylphenyl,4-hexadecylphenyl, 4-octadecylphenyl, 2-chlorophenyl, 4-methoxyphenyl,4-bromophenyl, 2-chloro-1-naphthyl, 4-chloro-1-naphthyl,6-chloro-1-naphthyl, 7,8-dichloro-1-napthyl, 4-bromo-1-naphthyl,7-chloro-2-naphthyl, 4-methyl-1-naphthyl, and 1-propyl-2-naphthylesters.

Suitable free-radical polymerization initiators include organicperoxides, for example, lauryl peroxide, and di-t-butyl peroxide;peresters, such as t-butyl peracetate and t-butyl peroxypivalate; andazo compounds, such as azobisisobutyronitrile. The copolymerization iscarried out most advantageously in a pressure reactor at a temperatureof 90°-250° C. and a pressure of 1600-2200 atm. The polymerizationtemperature is preferably maintained at about 145° C. and the pressureat 1800-2000 atm. Usually, the polymerization process is continuous, themonomer, optionally a solvent such as benzene, and the initiator beingintroduced at a controlled rate, and the reaction product beingcontinuously removed. A stirred autoclave such as described in U.S. Pat.No. 2,897,183 to Christl et al. can be used.

A representative trunk copolymer is a random copolymer of ethylene,methyl acrylate, and from 0.0025 to 0.077 moles/100 grams of polymer ofa monoethyl maleate, each 100 grams of copolymer having about 0.64-0.80moles of (--CO₂ --) units. Such copolymers may have, for example,compositions such as the following:

    ______________________________________                                        Mole %                                                                                                  Monoethyl                                           Ethylene    Methyl Acrylate                                                                             Maleate                                             ______________________________________                                        71.2        28.7          0.1                                                 57.8        42.1          0.1                                                 74.4        22.0          3.6                                                 61.4        34.4          4.2                                                 ______________________________________                                    

Another representative trunk copolymer is an alternating copolymerhaving repeating units consisting essentially of --A--B--, where Brepresents ethylene units and A represents units selected from at leastone C₁ -C₈ alkyl acrylate, and an acrylic cure-site monomer (2) or (3)(described above). The copolymerization is done in solution at -10° toabout 200° C. in the presence of a free radical initiator and BF₃ atpressures sufficient to keep the BF₃ complexed with the alkyl acrylate(generally 10 psig to 10,000 psig).

Conventional ethylene/α-olefin/diene monomer (EODM) copolymers, andespecially EPDM (ethylene/propylene/diene monomer) copolymers, also canbe used as the trunk polymers, provided an active site is introducedtherein. These copolymers are prepared in the presence of Ziegler (orcoordination) catalysts, which are combinations of transition metalcompounds (usually vanadium or titanium compounds such as VOCl₃, VCl₄,vanadium trisacetylacetonate, and titanium tetrachloride) and Group I-IIorganometallic reducing agents (such as alkylaluminum chlorides andbromides, lithium aluminum tetraalkyls, aluminum trialkyls). EPDM rubberis made by copolymerizing ethylene and propylene with at least onenonconjugated hydrocarbon diene (such as, for example, 1,4-hexadiene,5-propenyl-2-norbornene, 5-ethylidene-2-norbornene,5-methylene-2-norbornene, or dicyclopentadiene) as described in U.S.Pat. Nos. 2,933,480 to Gresham & Hunt; 3,000,866 to Tarney; 3,093,620 toGladding; 3,093,621 to Gladding et al.; 3,211,709 to Adamek et al.; and3,151,173 to Nyce. One of the double bonds is usually substantially lessreactive than the other; incorporation of the diene then leads to amonomer unit having the less reactive double bond in the side-chain.After the copolymer has been formed, active site monomers (2) or (3)(described above) can be grafted to the EPDM by thermal addition to theunsaturated side-chains. A typical trunk copolymer can be represented bythe following formula (4), which illustrates the case of a graft ofmaleic anhydride on an ethylene/α-olefin/1,4-hexadiene copolymer. Wavylines represent the polymer chain. ##STR5## The hydrocarbon copolymermay also include small amounts of units of a direactive nonconjugateddiene as in the ethylene/propylene/1,4-hexadiene/2,5-norbornadienecopolymer (and others) described in U.S. Pat. No. 3,819,591 to Campbelland Thurn.

Propylene is normally selected as the α-monoolefin in preparingside-chain unsaturated elastomeric ethylene copolymers because of itsavailability and low cost. Higher α-monoolefins (C₄ -C₁₈) also areuseful; 1-butene, -hexene, and 1-dodecene are examples.

The graft addition of amine-reactive monomers described above (e.g.,maleic anhydride and ethyl hydrogen maleate) is convenientlyaccomplished by heating a blend of the copolymer and amine-reactivemonomer within a range of about 225°-400° C. A process of this type isdescribed in detail in the copending application of Stanley WilliamCaywood, Jr., Ser. No. 322,360, filed Jan. 10, 1973, and now allowed inpart. Internal mixers or extruders are suitable. Exposure to maleicanhydride vapor should be minimized on account of its toxicity andpotential for causing severe eye damage. Unchanged maleic anhydride canbe extracted from the graft product with water or separated bydissolving the product in hexane (which will not solubilize maleicanhydride).

The proportion of the active sites in the trunk polymer can vary withina broad range. It is closely related to the desired proportion of the 6-or 12-nylon in the final graft copolymer. For any given proportion ofnylon grafts, there must be available a sufficient number of graftsites. The required number of graft sites also is related to the degreeof polymerization of the starting 6- or 12-nylon. To achieve the samefinal proportion of grafted nylon, one may choose a trunk polymer havingfewer graft sites and a 6- or 12-nylon having a relatively high degreeof polymerization (for example, 45) or a trunk polymer having more graftsites and a 6- or 12-nylon having a relatively low degree ofpolymerization (for example, 7). These relationships are verystraightforward and can be readily established by a skilled chemist orchemical engineer.

Many elastomeric polymers could be used in principle as the trunkpolymers, but some polymers are not attractive because they may undergoundesirable side reactions. Halogenated polymers, for example, have atendency to thermally dehydrohalogenate. Chlorosulfonyl groups aresuitable grafting sites, but chlorosulfonated polyethylene is not a goodtrunk polymer because it does not have sufficient thermal stability. Itis worth mentioning that isolated acid groups, such as carboxylicgroups, may form quasi salt-like addition products with amino-terminated6-nylons. Such products do not by themselves, however, have sufficientthermal stability unless grafts also are present. Under the usualgrafting conditions, no appreciable amide formation would occur betweensuch carboxylic groups and the nylons.

The amino-terminated 6- or 12-nylons are prepared by thermalpolymerization of ε-caprolactam or ω-laurolactam initiated by water orby amines of the formula R₁ R₂ NH, where R₁ and R₂ have the meaningdefined above in Summary of the Invention. Representative amines includebutylamine, hexylamine, octylamine, diethylamine, dibutylamine,cyclopentylamine, cyclohexylamine, propylamine, morpholine, pyrrolidine,N-methylpiperazine, and piperidine. The molar ratio range of the lactamto the amine initiator normally will be slightly broader than thedesired range of degree of polymerization and can be about 4:1 to 65:1.It is recommended that at least about 2 weight percent of water bepresent for practical reaction rates; 5% is satisfactory. About threehours at 245° C. are satisfactory, but the reaction time is rather long;higher temperatures, such as 280° C., allow a shorter reaction time.

When it is desired to prepare a carboxyl-terminated nylon, thepolymerization is initiated by water alone and is carried out in thepresence of a large amount of water, usually, about 20-50 weight percentof the starting lactam. The resulting 6- or 12-nylon has the structure##STR6## wherein Z is --OH and m and x have the above-defined meaning.

The degree of polymerization of the nylon (5) can be determined bytitration of the terminal amino groups by well known methods. It isoften practical to carry out the titration in an alcoholic solution byeither the potentiometric or the conductometric method.

It is believed that under the grafting conditions the nylon reacts withthe anhydride group at the graft site, either initially present orformed under graft conditions, to form the cyclic imide such as that ofFormula (1), above. In the preferred embodiment of the process, theanhydride group is already present in the trunk polymer. The nextpreferred is an adjacent pair of a carboxylic group and analkoxycarbonyl, which at higher temperature form the anhydride, withelimination of one molecule of alcohol. A third alternative is to use astarting trunk polymer preferably having vicinal carboxylic groups(although 1,3-carboxylic groups allow some grafting).

When the graft site is an adjacent pair of a carboxylic group and analkoxycarbonyl, these groups normally are derived from a monoalkylmaleate, fumarate, or citraconate comonomer. Vicinal carboxyl groups areintroduced by copolymerization with fumaric, maleic, itaconic, orcitraconic acids. The size of the ester alkyl group is at most about 20carbon atoms. Preferred are ethyl and methyl esters. Other estersinclude, for example, all isomeric forms of propyl, butyl, hexyl, nonyl,undecyl, tetradecyl, heptadecyl, and eicosyl.

Grafting can be accomplished in any convenient apparatus, preferably oneable to produce high shear conditions at a temperature above the meltingpoint of the starting nylon. Examples include roll mills, extruders, andinternal mixers having convoluted rollers, sigma blades, and the like.Usually, the reaction temperature will be at least about 215° C. Thereaction time mainly depends on the speed of mixing because the graftingreaction is quite rapid. The usual reaction time will be about 1-30minutes. Below 1 minute, adequate mixing may not be achieved in someequipment; however, reaction times as short as, for example, 15 secondsare possible. Above 30 minutes, no additional grafting can be expected,while some thermal degradation may occur. In any event, it is practicalto avoid air atmosphere during the grafting operation, for example, bymaintaining a nitrogen blanket over the reacting mass or by carrying outthe process in an extruder.

The ratio of the 6- or 12-nylon to the trunk polymer can be variedwithin a rather broad range. Since it is desired to produce elastomericproducts, rather than plastics, the minimum proportion of theelastomeric trunk polymer should be about 45 weight percent of the finalproduct. Above about 85 weight percent of the trunk polymer, themechanical properties of the graft copolymer tend to deteriorate.

Graft copolymers having the most desirable balance of physicalproperties are those in which the proportion of the 6-nylon is about35-55 parts per 100 parts by weight of the trunk copolymer, the latterthus constituting about 64.5-74 weight percent of the final graftcopolymer. Graft copolymers having the highest tensile strength containabout 50-90 parts of the 6-nylon per 100 parts by weight of the trunkcopolymer, the latter constituting about 52.5-67 weight percent of thefinal graft copolymer.

It is theoretically possible to graft amine-terminated 6-nylon onto anelastomeric backbone polymer in solution, but solvents which woulddissolve nylon (mainly, phenolic solvents) are rather inconvenient towork with. Therefore, solution grafting is less attractive.

The progress of grafting can be followed by infrared spectroscopy. Whenthe starting trunk polymer contains 5-membered, cyclic anhydride activesites, the disappearance of either one of two characteristic absorptionbands at 5.4 microns or at 5.6 microns indicates that grafting is takingplace. The proportion of the anhydride groups in the starting trunkpolymer can be determined by forming a polymer film of known thicknessand examining the infrared spectrum of such film. It has been foundexperimentally that 0.28 absorption units/mil (11 units/mm) at 5.4microns or 2.2 absorption units/mil (87 units/mm) at 5.6 micronscorrespond to 10 weight percent anhydride. The absorption units are readdirectly from an infrared spectrogram.

Similarly, when the starting trunk copolymer contains vicinal carboxyland alkoxycarbonyl groups, the characteristic infrared absorption bandlies at 5.9 microns. Assuming the vicinal carboxyl and alkoxycarbonylgroups to be derived from ethyl hydrogen maleate, the characteristicabsorption will be 1.1 absorption units/mil (43 units/mm) for every 10weight percent maleate present. Such analytical techniques would not bepractical in the case of a starting copolymer containing vicinalcarboxyl groups. However, the concentration of carboxyl groups can bereadily determined by simple titration.

The graft copolymer product can be characterized by several techniques,which show the presence of polyamide side chains, the degree ofpolymerization of the polyamide side chains, and the chemical identityof the polyamide, to name a few. Certain physical characteristics oftenare also helpful to show that a graft copolymer has been obtained.

The presence of polyamide is shown by infrared absorption at 6.0 microns(amide carbonyl). Other useful wavelengths include 6.4 microns (--NHbending) and 3.0 microns (--NH stretching). The proportion of polyamideis determined by Kjeldahl analysis for % N.

The polyamide can be chemically identified by heating a sample of agraft copolymer with a mineral acid, for example, sulfuric orhydrochloric acids, to about 200° C. or more. Under these conditions,the polyamide chain degrades to the starting lactam. Both ε-caprolactamand ω-laurolactam are volatile. They can be isolated and identified byany convenient technique of qualitative analysis.

Direct measurement of graft efficiency by extraction of unboundpolyamide is difficult since solvents for polyamides also attack trunkand graft copolymers. Reactive function titration results on graftcopolymers provide no more than rough estimates of graft efficiency.

Determination of the increase of molecular weight due to grafting is aconvenient technique. This is usually done by gel permeationchromatography of 0.5% graft copolymer solutions in m-cresol at 100° C.on porous polystyrene-packed columns.

A good indication that grafting has taken place is the torsion modulusof the products, especially at 100°-150° C. While the grafted copolymerwill have a fairly high modulus (e.g., 10⁷ -10⁸ dynes/cm.²), ungraftedmaterial will flow in that temperature range.

Ungrafted blends of trunk copolymers and polyamides (within theproportions capable of giving elastomeric graft copolymers) displaynegligible strengths and compression set resistance, acting like typicaluncured compositions. After grafting, the strength, clarity, hardness,compression set resistance, and solvent resistance increase. Strength atelevated temperatures, e.g., at 100° C., is significantly better thandisplayed by the physical blends before grafting.

Knowing the degree of polymerization (DP) of each starting 6- or12-nylon, it is possible to plot DP versus the peak melting point ofeach resulting graft copolymer, as determined with a differentialscanning calorimeter (DSC). It has been observed that the peak meltingpoint increases as the DP of the polyamide side chains increases. Such aplot can serve as a calibration curve which can be used for thedetermination of the DP of the polyamide grafts in the copolymers of thepresent invention.

The graft copolymers must be conditioned for testing by first heating to250° C., then cooling at the rate of 10° C. per minute to 50° C. Duringthe test, the sample is heated at the rate of 10° C. per minute.

DSC techniques are discussed in Thermoanalytical Methods ofInvestigation, by P. D. Garn, Academic Press, New York, 1965.

Another convenient and somewhat related technique for correlating the DPof the grafted polyamide with its melting point is differential thermalanalysis (DTA). The sample also must be preconditioned and is heatedduring the test at the rate of 20° C. per minute. The details of the DTAtechnique are described in Differential Thermal Analysis, R. C.MacKenzie, Editor, Academic Press, New York, 1970; especially in Chapter23, by C. B. Murphy, dealing with polymers, Vol. I, pp. 643-671.

It is to be noted that the above techniques relying on polymer meltingpoint determination, DSC and DTA, can only be used for polymers having ahigh degree of crystallinity. In the present case, only the crystallinepolyamide side chains will have well defined melting points, and thosewill be recorded. The elastomeric trunk polymers are usuallynoncrystalline at the test temperatures and will not produce any meltingpoint peaks on DSC or DTA graphs. In the case of trunk copolymerscontaining a substantial proportion of ethylene (for example, certainethylene/propylene/diene monomer copolymers having active site monomersgrafted thereon), their crystallinity may be sufficiently high toproduce a distinct melting point peak. This, however, will be well belowthe temperature range of interest and thus will not interfere with thedetermination.

The thermoplastic graft copolymers made by the process of this inventioncan be made into a wide variety of useful shaped articles by techniquesand in equipment familiar to those skilled in the art. Conventionalcasting and compression and injection molding are suitable fabricatingtechniques. A reciprocating screw type injection molding machine inwhich shearing provides additional heating is the preferred apparatus;typically a machine having a 4.5 kg charge can exert a clamping pressureof 1.225 million kg. Injection pressures of 900-1200 kg/sq.cm. andcycles times (mold closing to mold closing) of 150 seconds can be used.

The thermoplastic elastomeric compositions of the instant invention canbe used in a wide variety of industrial applications including wirejacketing, hose, belts, miscellaneous molded boots, seals and gaskets;they can be also employed to make low speed, low pressure tires foroff-the-road application; and they can be melt spun to give elasticfibers.

The preparation of representative starting trunk copolymers and 6-nylonsand of the graft polymers of this invention is now illustrated by thefollowing examples of certain representative embodiments thereof,wherein all parts, proportions, and percentages are by weight unlessindicated otherwise.

The determination of physical and/or chemical properties of the startingtrunk copolymers was carried out as follows:

a. inherent viscosity, deciliters per gram, was measured at 30° C. on asolution of 0.1 g of polymer in 100 ml. of chloroform, unless adifferent solvent is shown.

b. neutralization equivalent was determined by acid-base titration usingstandard aqueous sodium hydroxide, the anhydride being titrated asdiacid,

c. Wallace plasticity at 100° C. was determined according to thefollowing procedure:

The Wallace plasticity is a measure of the amount of flow or deformationunder load of unvulcanized elastomeric materials. The sample to betested is sheeted and cut into pellets having a thickness in the rangeof 3.18 mm to 7.62 mm (0.125 to 0.300 inch). The test is done with aWallace Plastimeter, manufactured by H. W. Wallace and Co., Ltd.,London. Initially, for a 15-second period, the test pellet is compressedto a thickness of exactly one millimeter and heated to 100° C. Then thetest pellet is subjected to a 10-kilogram load for exactly 15 seconds at100° C. The final thickness of the test piece, expressed in units of0.01 millimeter, is the plasticity reading.

d. melt index was measured at 190° C. under a 2160 g. load - ASTM MethodD 1238-70, Condition E.

The degree of polymerization (DP) or molecular weight of the starting6-nylons can be readily determined by end group analysis. The aminio endgroups are determined by titration with a strong acid, either in thepresence of an indicator or by a potentiometric orconductometric method.Acid end groups are determined by titration with a strong base. Thesetechniques are discussed in Nylon Plastics, M. I. Kohan, Editor, pp. 38and 105, John Wiley and Sons, New York (1973), and in Encyclopedia ofPolymer Science and Technology. Vol. 10, pp. 542 and 543, John Wiley andSons, New York (1969).

EXAMPLES Preparation of Trunk Copolymers

A. Preparation of Ethylene/Methyl Acrylate/Monoethyl Maleate Copolymer

A terpolymer containing 46.6% ethylene, 50% methyl acrylate, and 3.6weight percent monoethyl maleate and displaying a melt index of 3.6 g/10min was prepared in a 0.72-liter stirred autoclave.

A mixture of methyl acrylate, monoethyl maleate, and benzene (weightratio: 68.28/2.46/29.26) was pressured to about 422 kg/sq cm; ethylenewas separately pressured to about 422 kg/sq cm. Separate streams of thismixture (0.91 kg/hr) and ethylene (6.35 kg/hr) were joined and pressuredto 1900 kg/sq cm. The resulting feed stream then entered the autoclave.Simultaneously, a catalyst solution, made by adding 50 ml of tert-butylperoxypivalate to 4.5 kg of benzene was introduced at the rate of0.00204 kg/hr to keep the temperature at 170° C. The effluent from theautoclave passed through a let-down valve to a chamber at atmosphericpressure where most of the residual monomers and solvent flashed off.The ethylene/methyl acrylate/monoethyl maleate terpolymer thus isolatedwas freed from the small amount of residual volatiles by heating for 16hours at 80° C. in a nitrogen stream. Acid-base titration indicated that0.25 meq. of acid groups was present per gram of terpolymer,corresponding to 3.6 weight % monoethyl maleate in the copolymer.

B. Preparation of Ethylene/Vinyl Acetate/Maleic Anhydride Copolymer

A terpolymer containing 60.3% ethylene, 38 weight percent vinyl acetate,and 1.7% maleic anhydride, and displaying a melt index of 220 g/10 minwas prepared at the rate of 0.68 kg/hr in a continuous 0.72-literstirred autoclave by the following procedure. Monomers were mixed,pressured to 1900 kg/sq cm, and fed at these rates:

    ______________________________________                                        Ethylene              4.54 kg/hr                                              Vinyl acetate         2.29 kg/hr                                              Maleic anhydride      0.015 kg/hr                                             ______________________________________                                    

A solution of azobis(isobutyronitrile) in benzene was simultaneouslyintroduced at a rate sufficient to keep the reactor temperature at 170°C. (about 0.587 g/hr corresponding to 0.86 kg catalyst per 1000 kg ofterpolymer). The total benzene feed rate was 1.04 kg/hr. The terpolymerproduced was isolated by a procedure similar to that described inExample A.

C. Preparation of Ethylene/Vinyl Acetate/Maleic Anhydride Copolymer

A terpolymer containing 65.6% ethylene, 32% vinyl acetate, and 2.4%maleic anhydride, and displaying a melt index of 125 g/10 min wasprepared at the rate of 0.63 kg/hr in a continuous 0.72-liter stirredautoclave by the following procedure. Monomers were mixed, pressured to1900 kg/sq cm and fed at these rates:

    ______________________________________                                        Ethylene              4.54 kg/hr                                              Vinyl acetate         1.80 kg/hr                                              Maleic anhydride      0.0258 kg/hr                                            ______________________________________                                    

A solution of azobis(isobutyronitrile) in benzene was introduced intothe reactor at the same time and at a rate sufficient to keep thereactor temperature at 170° C. (about 1.00 g/hr corresponding to 1.58kg/1000 kg of terpolymer). The total benzene feed rate was 0.67 kg/hr.The terpolymer produced was isolated by a procedure similar to thatdescribed in Example A. Acid-base titration with standard aqueous sodiumhydroxide indicated that 0.49 meq of diacid derived from anhydridegroups was present per gram of terpolymer, corresponding to 2.4 weight %maleic anhydride in the copolymer.

D.sub.(1) Preparation of Alternating Ethylene//Ethyl Acrylate/AllylAcrylate/Maleic Anhydride Tetrapolymer

A 7.57-liter stirred autoclave was charged under nitrogen with 4000 mlof methylene chloride, 400 grams of ethyl acrylate, 20 grams of maleicanhydride, 1.2 grams of allyl acrylate, and 1.0 gram ofazobis(isobutyronitrile). It was then sealed, charged with 300 grams ofboron trifluoride, and pressured to 21 kg/sq cm with ethylene. Thesubsequent copolymerization at 25° C. was continued until pressuremeasurement indicated that ethylene uptake had ceased (about two hourslater). The reaction was quenched by addition of one liter of diethylether. Volatiles were removed by steam-stripping in a well-ventilatedhood. The terpolymer thereby obtained was dissolved in acetone,precipitated in water in a blender, and oven-dried. Yield: 415 grams.

This product had about 50 mole percent ethylene units and was slightlybranched because of the use of the direactive allyl acrylate. Thepolymer chain consisted principally of alternating units -(E)-(B)-,where E is ethylene and B is selected randomly from ethyl acrylate,allyl acrylate, and maleic anhydride.

D.sub.(2) Preparation of Alternating Ethylene//Ethyl Acrylate/EthyleneDiacrylate/Maleic Anhydride Tetrapolymer

The procedure of D.sub.(1), above, was repeated except that 1.2 grams ofethylene diacrylate was used in place of the allyl acrylate. Yield: 479grams. The branched alternating tetrapolymer obtained had about 50 molepercent of ethylene units. The polymer chain consisted principally ofalternating units -(E)-(B')-, where E is ethylene and B' is randomlyselected from ethyl acrylate, ethylene diacrylate, and maleic anhydride.

D.sub.(3) Preparation of Alternating Ethylene/Ethyl Acrylate/EthyleneDiacrylate/Maleic Anhydride Tetrapolymer

The procedure of D.sub.(1) above was repeated except that 0.75 gram ofethylene diacrylate was used in place of the allyl acrylate, and theamount of maleic anhydride was increased to 30 grams: Yield: 417 grams.The branched alternating tetrapolymer had about 50 mole percent ofethylene units, the units being arranged -(E)-(B')-, as in D.sub.(2).D.sub.(4) Blend of Branched Alternating Copolymers

The branched alternating copolymers made by procedures D.sub.(1),D.sub.(2), and D.sub.(3) were blended on a rubber roll mill. Table Igives the properties of the blend and its components.

                  TABLE I                                                         ______________________________________                                                Parts   Weight %               Neut. Eq.                              Copolymer                                                                             in      maleic     Inh. Wallace                                                                              meq.                                   D       Blend   anhydride  Visc.                                                                              Plast. g                                      ______________________________________                                        (1)     397     2.5        1.91 16.8   0.52                                   (2)     479     3.8        1.33 15     0.77                                   (3)     417     3.9        1.21 15     0.80                                   Blend (4)                                                                             --      3.4        1.75 14     0.70                                   ______________________________________                                    

E. Preparation of Alternating Ethylene//Ethyl Acrylate/AllylAcrylate/Maleic Anhydride Tetrapolymer

The procedure of Part D.sub.(1) was repeated except that the pressure ofethylene was 42.2 kg/sq cm. Yield: 233 grams. The tetrapolymer had aninherent viscosity of 2.37 deciliters/gram, a Wallace Plasticity of24.4, and a neutralization equivalent of 0.49 meq/gram, corresponding to2.4 weight % maleic anhydride in the copolymer.

F.sub.(1), (2) Preparation of Alternating Ethylene//Ethyl Acrylate/AllylAcrylate/Maleic Anhydride Tetrapolymers

The procedure of Part D.sub.(1) was twice repeated except that theamount of maleic anhydride was decreased each time to 10 grams. Yields:481 grams and 497 grams.

F.sub.(3) Preparation of Alternating Ethylene/Ethyl Acrylate/EthyleneDiacrylate/Maleic Anhydride Tetrapolymer

The procedure of Part D.sub.(1) was repeated except that 0.75 gram ofethylene diacrylate was used in place of allyl acrylate. Yield: 476grams.

F.sub.(4) Preparation of Blends of Branched Alternating Copolymers

A trunk copolymer composition was prepared by blending copolymersF.sub.(1), F.sub.(2), and F.sub.(3) on a rubber roll mill. Table IIgives characteristic properties.

                  TABLE II                                                        ______________________________________                                                 Parts   Weight %              Neut. Eq.                                       in      maleic    Inh. Wallace                                                                              meq.                                   Component                                                                              Blend   anhydride Visc.                                                                              Plast. g                                      ______________________________________                                        F.sub.(1)                                                                              336     1.8       1.97 15.5   0.36                                   F.sub.(2)                                                                              292     2.1       1.78 13.3   0.42                                   F.sub.(3)                                                                              241     2.3       1.52 14     0.46                                   Blend F.sub.(4)                                                                        --      2.1       1.44 13.5   0.43                                   ______________________________________                                    

G. Preparation of Ethyl Acrylate/Monoethyl Fumarate Copolymer

In a 3-neck round-bottom flask, a mechanically stirred mixture of 500 mlof benzene, 100 ml of inhibited ethyl acrylate, 7.2 grams of monoethylfumarate, and 0.25 gram of azobis(isobutyronitrile) was sparged withnitrogen for 30 minutes, then heated at 50° C. under a nitrogen blanketfor 24 hours. The copolymer was isolated by steam-stripping in awell-ventilated hood and dried overnight in a nitrogen-bled vacuum ovenat 70° C. Conversion was 86%. Prior to analysis and use, the copolymerwas purified by dissolution in acetone, precipitation in water in ablender, and vacuum oven drying. Properties are given in Table III,below.

H.sub.(1), (2) preparation of Ethyl Acrylate/Maleic Anhydride Copolymers

1. The reactor was a two-liter resin flask fitted with an agitator, acondenser and a dropping funnel. A 710-ml charge of ethyl acetate and0.2 gram of benzoyl peroxide was added and stirred under nitrogen whilebeing heated to reflux. A mixture of 500 grams of inhibitor-free ethylacrylate, 10 grams of maleic anhydride, and one gram of benzoyl peroxidewas placed in the dropping funnel. A 50-ml charge of this monomer feedwas added all at once to the stirred refluxing solution in the flask;the rest was added over a period of 3.5 hours. After additional twohours at reflux, the reaction mixture was steam-distilled in a hood withgood ventilation to remove solvent and residual monomers. The copolymerthus isolated was washed with water on a wash mill, partially dried on ahot rubber roll mill, and then heated in a nitrogen bled vacuum oven for22 hours at 130° C. to remove residual volatiles. Yield: 448 grams.

2. The same equipment was used as in H.sub.(1) above. The ethylacrylate/maleic anhydride copolymer was prepared as follows. A mixtureof 500 grams of ethyl acrylate, 10 grams of maleic anhydride, and 0.5gram of benzoyl peroxide was added to 490 grams of refluxing ethylacetate over a 4-hour period. After about 85% of this feed mixture hadbeen introduced, 140 ml of cyclohexane and 35 ml of ethyl acetate wereadded. When all the feed was in, 80 ml more of ethyl acetate were added.Reflux continued for one hour. Heat was then removed and the mixture wasallowed to stand for 36 hours. Finally, 0.5 gram of hydroquinone wasadded and the copolymer was isolated by steam-stripping the volatiles ina well-ventilated hood. Mill drying and vacuum oven drying (20 hours at130° C.) followed. Yield: 364 grams.

Properties of the copolymers prepared as described in Section G,H.sub.(1) and H.sub.(2) are given in Table III.

                  TABLE III                                                       ______________________________________                                        Co-            Weight %                                                       poly- Maleic   monoethyl Inh. Wallace      meq..sup.(a)                       mer   Anh., %  fumarate  Visc.                                                                              Plast. Acidity                                                                             g.                                 ______________________________________                                        G     --       4.3       2.32 undet'd.     30                                 H.sub.(1)                                                                           1.5      --        1.24 5            31                                 H.sub.(2)                                                                           1.4      --        2.03 14           29                                 ______________________________________                                         .sup.(a) acidbase titration with standard aqueous sodium hydroxide; value     for H.sub.(1) and H.sub.(2) were each 0.15 meq./g. when alcoholic             potassium hydroxide was used, proportion of maleic anhydride calculated       from sodium hydroxide values                                             

I. Preparation of Ethyl Acrylate/Butyl Acrylate/Monoethyl FumarateTerpolymer

The reactor was a nitrogen-blanketed two-liter resin flask fitted withan agitator, a condenser, and a dropping funnel.

Monomers ethyl acrylate and butyl acrylate were passed through aluminato remove polymerization inhibitors. Then, 70 grams of the ethylacrylate, 70 grams of the butyl acrylate, 10.5 grams of monoethylfumarate, 21 grams of "Igepal Co-730" [nonylphenoxypoly(ethylene glycol)having about 15 --O--CH₂ --CH₂ -- units], 1050 grams of water, and 1.0gram of ammonium persulfate were added to the resin flask and heated toreflux. A mixture of 113 grams of ethyl acrylate, 113 grams of butylacrylate, 9.4 grams of monoethyl fumarate, and 3.8 grams of "IgepalCO-730" was gradually introduced at a rate to keep the reactiontemperature at 89° to 93° C. After 1.4 hours, all the feed had beenadded and stirring was becoming difficult. After additional 20 minutes,the temperature of the reaction mixture had risen to 96° C., whereupon0.15 gram of hydroquinone was added, and residual monomers were removedby a 2-hour steam-distillation in a well-ventilated hood.

Coagulated polymer was washed by chopping in a blender with water, twicedissolved in acetone and reprecipitated in water in a blender, thenair-dried, vacuum-oven dried 3.5 hrs. at 72° C., and finally mill-driedat about 130° C. Yield: 254 g. The terpolymer produced had an inherentviscosity (chloroform, 30° C.) of 1.51 deciliters/gram and an acidcontent of 0.24 meq/gram (titration with aqueous sodium hydroxide), or0.23 meq/gram (titration with alcoholic potassium hydroxide). Theterpolymer had 3.3 weight % monoethyl fumarate; the remainder wasbelieved to be about equally divided between ethyl acrylate and butylacrylate.

J. Preparation of An EPDM/Maleic Anhydride Adduct

Maleic anhydride was grafted on an ethylene/propylene/1,4-hexadienecopolymer. The ethylene/propylene/1,4-hexadiene copolymer was asulfur-curable elastomer haing a Mooney (ML-1+4/121° C.) viscosity ofabout 35 and the following monomer unit composition: ethylene, 61.4weight %; propylene, 32 weight %; 1,4-hexadiene, 6.6 weight %. Thecopolymer had about 0.5 gram mole of ethylenically unsaturatedside-chains per kilogram. Its Wallace Plasticity was about 28 at 100° C.and its inherent viscosity was about 2.0 (measured at 30° C. on asolution of 0.1 gram of copolymer in 100 milliliters oftetrachloroethylene). Copolymerization was carried out in solution inhexane in the presence of a Ziegler catalyst formed by mixing VCl₄ anddiisobutylaluminum chloride.

A Werner and Pfleiderer 53 mm twin screw extruder was assembled byend-to-end attachment of sixteen barrel sections of 1.27 cm (1/2 inch)diameter. Following a short feed section were four reaction sections(zones 1-4), one vacuum port section (zone 5), a cooling section (zone6), and a die section. Provisions were made for the metering of moltenmaleic anhydride at the forward part of zone 1. The screws were composedof kneading blocks, reverse pitch screws, and transport screws arrangedto generate 7.0-14.1 kg/sq.cm (100-200 psi) pressure in zones 1-4 and nopressure in zone 5. The free volume of zones 1-5 was equivalent to 0.91kg (two pounds) of polymer at operating temperature. Zones 1-4 werepreheated to 300° C., zone 5 to 260° C., and zone 6, the cross-head, andthe die to 150° C.

The above ethylene/propylene/1,4-hexadiene copolymer was fed to theextruder in the form of chips which passed a 1.27 cm (1/2-inch) screen.Maleic anhydride was metered to the extruder at an average feed rate of4.8% of the polymer weight. The screw speed was 12 rpm. and the vacuumport was operated at about 63.5 cm (25 inches) Hg.

The product, extruded at the rate of 2.79 kg/hr. (6.15 lb./hr.), had amaleic anhydride content of 2.23%, as determined by infraredspectroscopy, and 2.19% by weight as determined by titration intetrahydrofuran with 0.1 M tetrabutylammonium hydroxide in methanol.Wallace plasticity of the product was 33, and gel content was less thanabout 5%.

Following purification of a small sample by solution in tetrahydrofuranand precipitation with anhydrous acetone, the maleic anhydride contentwas 2.19% and 2.05% by weight, respectively, by infrared and titrationand determination. The gel content was less than about 5%. The inherentviscosity was 1.5 deciliters/gram as measured on 0.1 gram of adductdissolved in 100 milliliters of perchloroethylene at 30° C.

The rest of the product was washed on a wash mill at 125° C. for 20minutes and dried on a 15.2×30.5 cm (6×12-inch) mill.

Preparation of H₂ N-Terminated 6-Nylons

Amine-terminated polyamides were prepared by procedures K-S which arecompletely summarized in Table IV below. Additional details are providedfor Procedures L, N, Q and S, which are typical processes.

PROCEDURE L

In each of two 400-ml stainless steel rocker bombs was placed a mixtureof 120 g of caprolactam, 10 g of octadecylamine, 0.3 g of diethylphosphate, and 120 ml of benzene. Both bombs were flushed with nitrogen,sealed under nitrogen, and shaken at 275° C. for 17 hours. Thebenzene-wet cakes of granular product were combined and soaked inacetone for 5 days, then extracted overnight with acetone in a Soxhletassembly. The resulting powdery amine-terminated nylon product wasair-dried in a hood, then vacuum-oven dried at 50° C. for one hour.Analysis are in Table IV.

PROCEDURE N

A charge of 300 g of caprolactam and 100 ml of water was sealed undernitrogen in a 1.4-l stainless steel rocker bomb and heated over a periodof 2.1 hours to 280° C., held there for 3 hours, then cooled to roomtemperature. After additional 650 ml of water had been added undernitrogen, the bomb was again sealed and shaken while being subjected tothe following temperature schedule: 1.2 hours heating to reach 210° C.,15 minutes at 210° C., cooling over 20 minutes to 135° C., 2 hours at135° C., then cooling over 1.2 hours to room temperature. The resultingproduct, a partial slurry of powder, granules, and cake, was partlyde-watered by filtration, then chopped in a blender with fresh warmwater. Acetone was added to increase slurry volume by 50%, and thesolids were isolated by filtration. After being air-dried in a hood,then dried in a vacuum oven for 8 hours at 100° C. (nitrogen bleed), theamine-terminated nylon product weighed 217 grams. Analyses are in TableIV.

PROCEDURE Q

A charge of 769 grams of caprolactam, 32 grams of butylamine, and 15grams of water was sealed under nitrogen in a 1.4-liter stainless steelrocker bomb, heated over a 2.5-hour period to 280° C., shaken at 280° C.for 7 hours, then cooled over a 3.2-hour period to room temperature. Theproduct, a brittle cake, was mechanically chopped to a coarse granularcondition. A 317.9-gram portion of the total product was rolledovernight in a sealed 7.57-liter (2-gallon) jar with 1.42 liters (3pints) of methanol. Insoluble material was collected on a filter, washedin two portions with 0.47 liter (one pint) of methanol, brieflyair-dried, and then dried in a nitrogen-bled vacuum oven for 3 hours at75° C. Dry extracted product weighed 267.6 grams. Analyses of a smallersample (15 grams) similarly extracted with methanol are shown in TableIV.

PROCEDURE S

A mixture of 70 grams of caprolactam, 6 grams of 1-octadecylamine, and195 milliliters of diphenyl ether was placed in a 0.4-liter stainlesssteel rocker bomb.

                                      TABLE IV                                    __________________________________________________________________________    Low Molecular Weight Amine-Terminated 6-Nylon Preparations                                    K    L    M   N   O   P      Q    R    S                      __________________________________________________________________________    Nitrogen-Blanketed                                                            Polymerization                                                                Charge Compositions, g.                                                       caprolactam     140  240  295 300 283 283    769  769  70                     octadecylamine  10   20                                6                      octylamine                23      32.2                                                                              20.8                                    butylamine                                   32   32                          ε-aminocaproic acid                                                                             5                                                   water                         100 4   4      15   15                          diethyl phosphate                                                                             0.2  0.6                               195                    diphenyl ether  135                                                           benzene              240                                                      Post-polymerization                                                           Diluent, g.sup.(a)                                                            benzene                   300                                                 water                         650                                             methanol                          451 451                                     Polymerization Conditions                                                     Hastelloy or stainless steel                                                                  0.4  2 × 0.4                                                                      1   1.4 1.4 1.4    1.4  1.4  0.4                    rocker tube vessel size, 1                                                    reaction temperature, °C..sup.(b)                                                      260  275  245, 230                                                                          280, 210                                                                          280, 230                                                                          280, 230                                                                             280  245  260, 235               reaction time, hrs..sup.(c)                                                                   19.5 17   20, .5                                                                            3, .3                                                                             3.5, .5                                                                           3.5, .5                                                                              7    3    56                     Granulation Technique.sup.(a)                                                                 diluent                                                                            diluent                                                                            diluent                                                                           diluent                                                                           diluent                                                                           diluent                                                                              chopping                                                                           chopping                                                                           diluent                Purification Technique                                                        Overnight Soxhlet extraction                                                                  acetone                                                                            acetone                           acetone                solvent                                                                       Overnight reflux in 10X wt.                                                                             water                                               solvent                                                                       Overnight roller extraction,                 methanol                         solvent                                                                       Blender washing, solvent      (g) (h)                                         Centrifugation/decantation            methanol(3)                             washing, solvent (reps.)                                                      After filtration collection,                                                  air drying:                                                                   Vacuum oven (N.sub.2 -bleed)drying:                                           Temp/Time (°C./hrs.)                                                                        50/1 100/40                                                                            100/8                                                                             100/15                                                                            100/24 75/3                             Purified 6-Nylon Properties                                                   yield, g.       101.5                                                                              ˜180                                                                         ˜258                                                                        217 250 222.2  ˜652                                                                         798.3                                                                              --                     NH.sub.2 end-groups, meq./g..sup.(c)                                                          .198 .241 .428                                                                              .45 .61 .46    ˜.46                                                                         .495.sup.(f)                                                                       0.383                  COOH end-groups, meq./g..sup.(d)                                                                            .287                                            ηinh (m-cresol, 30° C.)                                                            .38  .36  .27 .30 .19 .23    ˜.29                                                                         --   0.21                   Differential scanning                                                                         216  217  210 220 209.5                                                                             214    ˜217                                                                         --   --                     colorimeter melting                                                           point, °C..sup.(e)                                                     Mol. Wt. from NH.sub.2 titration                                                              5050 4150 2335                                                                              2220                                                                              1640                                                                              2170   2170 2020 2600                   DP              42.4 34.5 19.5                                                                              19.5                                                                              13.5                                                                              18     18.5 17   21                     __________________________________________________________________________     .sup.(a) Inert diluent provided the nylon in finelydivided form if the        polymerizate was shaken with the diluent above the melting point of the       nylon.                                                                        .sup.(b) The Table does not include times required to reach reaction          temperature (usually  1.3-2.3 hour) or cool down (˜1-3 hours). A        second pair of temperature and time values refers to a second heating         period after addition of postpolymerization diluent.                          .sup.(c) A ˜0.8 gram nylon sample is dissolved by warming in 25 ml      of ocresol, and treated with 1.5 ml of water, then 7.5 ml of chloroform,      cooled, and titrated potentiometrically (Beckmann No. 39501 combination       electrode) with standard 0.03 N ethanolic potassium hydroxide.                .sup.(d) A˜0.1 gram nylon sample is dissolved by warming in 80ml        mcresol. After cooling, 10 ml of chloroform is added and the resulting        composition is titrated potentiometrically (glassmodified calomel             electrode) with standard 0.01 N 2,4dinitrobenzenesulfonic acid in acetic      acid.                                                                         .sup.(e) Samples were programmed at 10° C./min. through a cycle of     50° C. → 250° C. → 50° C. →         250° C., and the peak melting endotherm of the second heating cycl     taken as the melting point. A shoulder at a lower temperature was usually     observed.                                                                     .sup.(f) Caprolactam residual amine initiator, and low oligomers had not      been extracted before analysis.                                               .sup.(g) (1) hot H.sub.2 O, (2) acetone/H.sub.2 O (1/3).                      .sup.(h) (1) methanol, (2) methanol/acetone (5/2).                       

After the system had been evacuated and filled with nitrogen two times,it was closed under vacuum and shaken for about 8 hours at 260° C.;heating and shaking continued for two days, the final temperature being235° C.

The resulting mixture was washed on a filter with acetone and shaken forthree days in acetone to remove diphenyl ether. The product wascollected on a filter, washed with acetone, and extracted overnight in aSoxhlet extractor with acetone. Drying in air and then a vacuumdesiccator at 50° C. gave the 6-nylon as a powder having an inherentviscosity of 0.21 deciliters/gram (at 30° C. in m-cresol) and 0.383,0.388 eq. --NH₂ groups/kg. (corresponding to a molecular weight of about2600 and a D.P of about 21).

Preparation of NH₂ -Terminated 12-Nylons PROCEDURE T

A mixture of 59.6 grams of ω-laurolactam and 4.8 grams of1-octadecylamine was heated in a glass polymer tube. After the resultingmelt had been allowed to crystallize, 0.16 gram of diethyl phosphate(CH₃ CH₂ O)₂ PO₂ H was added. The tube was then evacuated and filledwith nitrogen about five times. While under vacuum the neck of the tubewas sealed. The mixture was then heated at about 285° to 288° C. forabout 9.5 hours. The 12-nylon obtained (yield about 45 grams) had amelting point of about 145°-150° C., an inherent viscosity of 0.34deciliters/gram (at 30° C. in m-cresol), and 0.225, 0.226 equivalent of--NH₂ groups per kg. (corresponding to a molecular weight of 4430 and aD.P. of about 21).

PROCEDURE U

A mixture of 50 grams of ω-laurolactam and 10.5 ml. (13.8 g.) ofn-hexylamine was placed in a heavy stainless steel tube, which wasevacuated, flushed with nitrogen, and filled with nitrogen, then sealedand heated sixteen hours at 255° C. The resulting nylon contained 0.492equivalent of --NH₂ groups per kilogram. The molecular weight of thenylon thus was about 2030 and its D.P. was about 9.5.

ADDITIONAL 12-NYLONS

Additional 12-nylons were made by method U using n-hexylamine as thepolymerization initiator. The products had D.P.'s of 5.3, 7.0, 10.2,14.3, 15.6, 24.0, and 15.6, respectively.

EXAMPLES 1-13 Preparation of 6-Nylon Graft Copolymers

Table V below summarizes the preparation, composition, and properties ofrepresentative 6-nylon graft polymers of the present invention.

                                      TABLE V                                     __________________________________________________________________________    Graft Copolymer Preparation, Composition, and Properties                      Example  1    2    3   4.sup.(a)                                                                         5   6   7   8   9    10 11  12  13                 __________________________________________________________________________    Trunk    E    F(4) D(4)                                                                              F(1)                                                                              H(2)                                                                              H(1)                                                                              C   B   A    A  G.sup.(e)                                                                         I.sup.(e)                                                                         I                  Copolymer                          E/-                 EA/                    "type.sup.(b)                                                                          Branched                                                                           Blend                                                                              as in                                                                             as in                                                                             EA/ as in                                                                             VAc/                                                                              as in                                                                             E/MA/                                                                              as in                                                                            EA/ BA/ as in                       Alt. E/                                                                            Branched                                                                           Ex. 2                                                                             Ex. 1                                                                             MAnh                                                                              Ex. 5                                                                             MAnh                                                                              Ex.7                                                                              MAME Ex. 9                                                                            FAME                                                                              FAME                                                                              Ex. 12                      EA/AA/                                                                             Alt. E/                                                                  MAnh EA/                                                                           MAnh                                                            "graft site                                                                            MAnh as in                                                                              as in                                                                             as in                                                                             as in                                                                             as in                                                                             as in                                                                             as in                                                                             MAME as in                                                                            FAME                                                                              as                                                                                as in                            Ex. 1                                                                              Ex. 1                                                                             Ex. 1                                                                             Ex. 1                                                                             Ex. 1                                                                             Ex. 1                                                                             Ex. 1    Ex. 9  Ex.                                                                               Ex. 11             "graft site                                                                            .235 .215 .35 .18 .15 .155                                                                              .245                                                                              .173                                                                              .25  .25                                                                              .29 .24 .24                conc. meq/g                                                                   Nylon    P    Q    R   K   L   N   Plasto-                                                                           M   O    O  O   O   O                  "initiator.sup.(d)                                                                     Octyl-                                                                             Butyl-                                                                             as in                                                                             Octa-                                                                             as in                                                                             H.sub.2 O                                                                         as in                                                                             as in                                                                             as in                                                                              as in                                                                            as in                                                                             as                                                                                as in                       amine                                                                              amine                                                                              Ex. 2                                                                             decyl-                                                                            Ex. 4   Ex. 1                                                                             Ex. 1                                                                             Ex. 1                                                                              Ex. 1                                                                            Ex. 1                                                                             Ex.                                                                               Ex. 1                                     amine                                                  "NH.sub.2 conc.                                                                        .46  ˜.46                                                                         ˜.495                                                                       .198                                                                              .24 .45 .61 .428                                                                              .61  .61                                                                              .61 .61 .61                meq./g                                                                        phr Nylon.sup.(e)                                                                      50.6 40   50  80  55  30  39  34  40   39 50  39  39                 Graft Reaction                                                                         Extruder                                                                           Plasto-.sup.(g)                                                                    Plasto-                                                                           Plasto-                                                                           Plasto-                                                                           Mill.sup.(g)                                                                      Mill                                                                              Plasto-                                                                           Extrud-                                                                            Mill                                                                             Mill                                                                              Mill                                                                              Plasto-            Apparatus     graph                                                                              graph                                                                             graph                                                                             graph       graph                                                                             er              graph              Graft Reaction                                                                Conditions:                                                                   Reactor Wall T,                                                                        ˜230                                                                         220  220 ˜210.sup.(i)                                                                ˜210.sup.(i)                                                                220 215 220 ˜230                                                                         215                                                                              210 210 220                °C..sup.(h)                                                            Residence Time                                                                         ˜16.4                                                                        10   10  20  20  15  15  18  ˜6.7                                                                         15 12  12  10                 min.                                                                          Graft                                                                         Copolymer                                                                     Physical                                                                      Properties.sup.(j)                                                            Shore A  83   76   81  85  77  64  91  85  67   63 92  83  71                 Hardness                                                                      T.sub.b,kg./sq.cm.                                                                     224  220  165 189 159 120 167 162 141  134                                                                              139 97  88                 E.sub.b, %                                                                             370  460  430 300 220 270 390 330 480  500                                                                              180 210 240                M.sub.100, kg./sq.cm.                                                                  86   67   58  110 79  58  78  84  48   28 115 70  34                 Comp. Set. %                                                                           23   22   35  33  26  35  32  34  28   34 37  38  43                 (22 hrs./70° C.,                                                       Method B)                                                                     __________________________________________________________________________     .sup.(a) A small amount of (0.4 phr) of aniline was added after the           grafting reaction.                                                            .sup.(b) E═ethylene: EA═methyl acrylate; (alt.) refers to             alternating, rather than random copolymer; VAC═vinyl acetate;             MA═methyl acrylate; BA═butyl acrylate; AA═allyl acrylate;         MAnh═maleic anhydride, MAME═monoethyl maleate; FAME═monoethyl     fumarate. These units are copolymerized in the trunk copolymer.               .sup.(c) Mill blends were treated 15 hours in a nitrogenbled 130°      C. vacuum oven just before the grafting reaction. Subsequent experiments      showed that his treatment had negligible effect on product physical           properties.                                                                   .sup.(d) The alkyl group of the initiator becomes one endgroup of nearly      all the polymer chains. The other endgroup is nearly always NH.sub.2.          .sup.(e) Parts of nylon by weight per hundred parts of trunk polymer.        .sup.(f) Brabender Plastograph, an apparatus having a small, electrically     heated chamber with two convoluted rollers capable of shearmixng and          masticating polymer at a selected high temperature.                           .sup.(g) An electricallyheated mill was used for the required temperature     .sup.(h) Polymer is not necessarily at this temperature at all times.         There is usually an initial warmup period followed by a modest overshoot,     perhaps because of an exothermic reaction.                                    .sup.(i) Accurate temperature readings were not obtained here.                .sup.(j) All graft products, in addition to the components listed here,       contained a mixture of stabilizers quite similar to that described in the     detailed Example (7). The following ASTM methods were used; Shore A,          D2240-68; Tensile Stress (T.sub.b), D412-68 Tensile Strain (E.sub.b),         D412.68 Stress at 100% Elongation (M.sub.100). D412-68; Compression Set       after 22 hrs. at 70° C. D395-67 (all values measured at 25°     C.). Specimens annealed for 4 hrs. at 135° C.                     

For all graft products, slabs for testing could be prepared by briefcompression molding at 235° C., followed by rapid (˜2 min.) cooling andimmediate demolding. Annealing of these slabs at 135° C. for 4 to 5hours generally improved compression set about 20 to 35 points but hadlitle effect on other properties. The grafting procedure used in Example7 of Table V is illustrative of the process:

Example 7

A mixture of 36 grams of the ethylene/vinyl acetate/maleic anhydridetrunk copolymer of Procedure C, 14 grams of the powdered low molecularweight, H₂ N-terminated 6-nylon of Procedure N, 0.1 gram of tris (mono-and di-nonylphenyl) phosphite stabilizer ["Polygard" from Uniroyal], 0.1gram of stabilizer N-phenyl-N'-(p-toluenesulfonyl)-p-phenylenediamine["Aranox" from Uniroyal], 0.1 gram of1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene["Ionol 330" from Shell], and 0.05 gram of a 7:1 weight mixture ofpotassium iodide and cuprous iodide was homogenized as thoroughly aspossible on an unheated rubber roll mill. The resulting blend was thentransferred to an electrically heated mill held at 215° and masticatedat 215° C. under a partial nitrogen blanket for 15 minutes to effectgrafting. At this point the material was ready for fabrication.

EXAMPLES 14-22 Preparation of Additional 6-Nylon and of 12-Nylon GraftCopolymers Based on Ethylene/Methyl

                                      TABLE VI                                    __________________________________________________________________________    Experiment        14   15   16   17   18   19   20   21   22                  __________________________________________________________________________    Trunk Polymer                                                                 % Ethylene        36.3 36.3 40.6 40.6 42.8 42.8 42.8 42.8 40.6                % Methyl Acrylate 39.7 39.7 50.8 50.8 51.4 51.4 51.4 51.4 50.8                % MAME            24   24   8.64 8.64 5.76 5.76 5.76 5.76 8.64                Melt Index        32.8 32.8 6.6  6.6  4.5  4.5  4.5  4.5  6.6                 Nylon             6    6    6    6    6    6    12   6    12                  DP                7.0  7.0  10.2 14.3 24.0 24.0 15.6 39.5 5.3                 End Group         H.A..sup.(a)                                                                       H.A..sup.(a)                                                                       COOH COOH COOH COOH H.A..sup.(a)                                                                       COOH H.A..sup.(a)        % Polyamide       25   35   25   33   25   35   25   40   25                  Reaction Type     Roll Mill                                                                          Roll Mill                                                                          Roll Mill                                                                          Roll Mill                                                                          Roll Mill                                                                          Roll Mill                                                                          Roll Mill                                                                          Extruder                                                                           Extruder            DTA Melt, Pt. °C.                                                      Peak              158.165                                                                            180  207  209  214  212  168  208  158                 End               220, 231                                                                           195  213  213  219  219  175  217  163                 Flex. Modulus, kg/cm.sup.2                                                                      552  1083 91   178  132  23   30   1019 510                 Tensile Strength, kg/cm.sup.2                                                                   61   92   68   62   61   25   44   145  98                  Elongation at break, %                                                                          190  130  400  230  120  300  620  310  190                 Torsion Modulus × 10.sup.-9, dynes/cm..sup.2                            -180° C.   12.66                                                                              14.77                                                                              14.90                                                                              16.19                                                                              15.54                                                                              15.29                                                                              27.59                                                                              14.41                                                                              14.69               -100° C.   9.80 11.94                                                                              10.18                                                                              11.84                                                                              11.07                                                                              9.23 16.97                                                                              9.59 8.96                -50° C.    7.41 8.42 4.76 6.65 5.42 5.60 9.39 5.54 6.20                0° C.      1.57 2.13 .07  .20  .18  .05  .10  1.00 .22                 20° C.     .90  1.64 .05  .16  .16  .04  .10  .89  .18                 50° C.     .28  .60  .04  .11  .12  .03  .08  .65  .12                 100° C.    .09  .20  .02  .05  .06  .01  .04  .20  .06                 150° C.    .04  .11  .015 .04  .04  --   --   .12  .02                 __________________________________________________________________________     ##STR7##                                                                 

Acrylate/Monoethyl Maleate Copolymers

Copolymers of ethylene, maleic, anhydride (MA), and monoethyl maleate(MAME were prepared according to the method A, above, except that theproportions of the comonomers were varied. Grafting of low molecularweight 6-nylons and 12-nylons was accomplished either on a roll millunder nitrogen blanket at about 225° C. or in a twin screw extruder atabout 225° C. Detailed information on these preparations is presented inTable VI, below.

For testing for tensile strength and flex modulus, the specimens wereinjection-molded at 225°-235° C. and held under nitrogen for at leastone day at 23° C. The following test procedures were used:

Tensile strength and elongation at break--ASTM D-638-72

Flex modulus--ASTM D-790-71

The determination of the torsion modulus was made in accordance with thefollowing reference:

ANELASTIC AND DIELECTRIC EFFECTS IN POLYMERIC SOLIDS, N. G. McCrum, B.E. Read, G. Williams, published by John Wiley and Sons, pages 192-195(1967).

EXAMPLES 23 AND 24 Preparation of 6-Nylon and 12-Nylon Graft Copolymerson EPDM Copolymers

A Brabender Plastograph was used having a capacity of about 50 grams andheated by circulating oil (temperature 250° C.). Revolving cam-shapedblades kneaded and sheared. A nitrogen blanket was maintained at alltimes.

After 30 grams of the EPDM copolymer-maleic anhydride adduct J, above,had been added, an antioxidant mixture, an oil mixture, and anamino-terminated 6- or 12-nylon (S or T, above) were added successivelyas quickly as possible. Mixing then continued for 12 minutes. Theresulting nylon graft copolymer was dumped. Table VII gives theproperties of a 6-nylon and a 12-nylon graft.

The antioxidant mixture employed (0.7 gram) consisted of 0.3 gram ofN-phenyl-N'-(p-toluenesulfonyl)-p-phenylenediamine ["Aranox"], 0.3 gramof 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl) benzene[Ethyl Antioxidant 330, formerly "Ionox 330"], and 0.1 gram of a 7:1weight mixture of potassium iodide and cuprous iodide.

The oil mixture consisted of the antioxidant tris(mono- anddi-nonylphenyl) phosphite ["Polygard" from Uniroyal] and "Sunpar"paraffinic oil 2280 [ASTM D-2226 type 104B, having Saybolt UniversalViscosity values of 2907 sec. and 165 sec. at 37.8° C. (100° F.) and98.9° C. (210° F.), respectively; specific gravity, 0.8916 at 15.6° C.(60° F.); density, 0.8879 g/cc; molecular weight, 720; viscosity-gravityconstant, 0.796; refractive index n_(D) ²⁰, 1.4908]. All mixturescontained 0.3 gram of the antioxidant; the oil amounted to 10.5 gramsfor 6-nylon grafting and 8.5 grams for 12-nylon grafting.

                  TABLE VII                                                       ______________________________________                                                            6-Nylon     12-Nylon                                      Poperties           Graft       Graft                                         ______________________________________                                        Tensile Strength    97.7        79.4, 66.1                                    kg./sq.cm.                                                                    Extension at Break, %                                                                             680         620,660                                       Modulus at                                                                    100% Extension, kg./sq.cm.                                                                        26.7        33.7                                          200% Extension, kg./sq.cm.                                                                        36.6        40.1                                          300% Extension, kg./sq.cm.                                                                        47.1        46.4                                          Permanent Set at Break, %                                                                         40          80                                            Compression Set                                                               (Method B, 22 hrs./70 ° C.), %                                                             77          83                                            Shore A hardness    66          84                                            Fast Tear, 127 cm./min.                                                                           11.8        21.4                                          kg./cm.                                                                       ______________________________________                                    

We claim:
 1. An elastomeric, thermoplastic graft copolymer consistingessentially ofA. an elastomeric trunk copolymer derived from at leasttwo monomers, at least one of said monomers providing amine-reactivesites selected from the class consisting of an anhydride group, avicinal pair of carboxylic groups, and a carboxylic group adjacent to analkoxy-, phenoxy-, napthoxy-, substituted phenoxy-, or substitutednaphthoxycarbonyl group, where the alkyl of the alkoxycarbonyl group has1-10 carbon atoms, and the substituents of substituted phenoxycarbonyland naphthoxycarbonyl groups can be a C₁ -C₁₀ alkyl, halogen, or a C₁-C₁₀ alkoxy group; at least one of said monomers containing noamine-reactive sites and none of said monomers containing hydroxyl oramino groups; and B. a side chain polymer derived from a short chainpolyamide represented by the formula ##STR8## where Z is ##STR9## R¹ andR² being independently selected from hydrogen, a C₁ -C₁₈ alkyl, benzyl,and C₅ -C₆ cycloalkyl; or taken together, being --(CH₂)₄ --, --(CH₂)₅--, --(CH₂)₂ --O--(CH₂)₂ --, or ##STR10## where R³ is a C₁ -C₆ alkyl;with the proviso that only one of R¹ or R² can be hydrogen; m is 5 and11; and x is a positive number having an average value of 5-60; saidside chain polymer being attached to said trunk copolymer through amideor imide linkages resulting from a reaction of the terminal primaryamino group of said short chain polyamide with the amine-reactive sitesof said trunk copolymer; the proportion of said elastomeric trunkcopolymer in the graft copolymer being about 45-85 weight percent.
 2. Agraft copolymer of claim 1 wherein m is
 5. 3. A graft copolymer of claim2 wherein R¹ is hydrogen and R² is octadecyl.
 4. A graft copolymer ofclaim 2 wherein R¹ is hydrogen and R² is octyl.
 5. A graft copolymer ofclaim 1 wherein m is
 11. 6. A graft copolymer of claim 5 wherein R¹ ishydrogen and R² is octyl.
 7. A graft copolymer of claim 1 wherein theweight proportion of the trunk copolymer is about 64.5-74%.
 8. A graftcopolymer of claim 1 wherein the weight proportion of the trunk polymeris about 52.5-67%.
 9. A graft copolymer of claim 1 wherein the trunkpolymer is a copolymer of an active site monomer selected from maleicanhydride, maleic acid, fumaric acid, and monoesters of maleic orfumaric acids with alcohols having up to about 20 carbon atoms with atleast one monomer selected from α-olefins; conjugated or nonconjugateddienes; styrene, and its ring-substituted derivatives; acrylic andmethacrylic acids, esters, and nitriles; vinyl esters; and vinyl ethers.10. A graft copolymer of claim 9 wherein the trunk polymer is acopolymer of ethylene, methyl acrylate, and monoethylmaleate.
 11. Agraft copolymer of claim 9 wherein the trunk polymer is a copolymer ofethylene, vinyl acetate and maleic anhydride.
 12. A graft copolymer ofclaim 9 wherein the trunk polymer is a copolymer of ethylene, ethylacrylate, allyl acrylate, and maleic anhydride.
 13. A graft copolymer ofclaim 1 wherein the trunk polymer is an ethylene/α-olefin/diene monomer(EODM) polymer, having grafted thereon at least one of maleic anhydrideand ethyl hydrogen maleate active sites.
 14. A graft copolymer of claim12 wherein the EODM polymer is an ethylene/propylene/diene monomer(EPDM) polymer.
 15. A graft copolymer of claim 13 wherein the EPDMpolymer is an ethylene/propylene/1,4-hexadiene polymer.